With the movement toward higher integration of semiconductor devices and larger scale of substrates, there is an increasing demand for a reduction in production costs of semiconductor devices. To meet the demand, a heat treatment process, in particular, a rapid heat treatment process is mainly used.
The rapid heat treatment process requires the precise control of the temperature of a substrate because the temperature of the substrate increases and decreases in a relatively wide temperature range for a very short time. Furthermore, to perform the rapid heat treatment process while maintaining a uniform temperature distribution of the substrate, it is necessary to maintain constant thermal properties over the entire area of the substrate. To achieve temperature uniformity over the entire area of the substrate, it is necessary to appropriately arrange lamps for heating the substrate and appropriately control the power supplied to each lamp to form a uniform heat flux over the entire area of the substrate. However, because there are many parameters including an amount and flow of gas introduced into a chamber for rapid heat treatment process and an internal structure of the chamber below and beside the substrate and these parameters are variable, it is not easy to ensure temperature uniformity over the entire area of the large scale substrate through only optimization of hardware type chamber design.
Accurately measuring the temperature of the large-scale substrate in the chamber for rapid heat treatment process is recognized as an important factor determining the reliability of the rapid heat treatment process and quality of semiconductor devices. A method for measuring the temperature of the substrate in the chamber for rapid heat treatment process is classified into a contact type and a non-contact type according to whether the substrate contacts temperature measuring means, and to prevent damage of the substrate caused by the contact between the temperature measuring means and the substrate, a non-contact temperature measurement method is mainly used. Furthermore, to obtain uniform process properties over the entire area of the substrate, a rotary rapid heat treatment apparatus that rotates the substrate in the chamber for rapid heat treatment process during the rapid heat treatment process is mainly used, rather than a fixed rapid heat treatment apparatus that does not horizontally rotate the substrate and fixes the substrate. Examples of the substrate temperature measurement method applied to the non-contact rapid heat treatment apparatus are disclosed by Korean Patent No. 10-0337107 (Patent Literature 1), Korean Patent No. 10-0395662 (Patent Literature 2), Korean Patent Publication No. 10-2002-0019016 (Patent Literature 3), Korean Patent No. 10-0423184 (Patent Literature 4), and Korean Patent No. 10-1097718 (Patent Literature 5).